Australian Prime Minister Tony Abbott warned Thursday of the Islamic State group's "global ambitions" and said more must be done to combat the organization's extremist mass appeal.

Abbott was speaking in Sydney at the opening address of a regional conference that aims to help governments come up with a more unified plan to counter and prevent the distribution of terrorist propaganda.

"Daesh is coming, if it can, for every person and for every government with a simple message: 'Submit or die,'" said Abbott, using an alternate name for the extremist group. "The declaration of a caliphate, preposterous though it seems, is a brazen claim to universal dominion. Now, you can't negotiate with an entity like this; you can only fight it."

The prime minister said Australia is looking for ways to get tougher with its citizens who go to fight with overseas terrorist groups, an action he referred to as a "modern form of treason."

But the conservative leader conceded that the "only really effective defense against terrorism is persuading people that it's pointless."

"Above all, we need idealistic young people to appreciate that joining this death cult is an utterly misguided way to express their desire to sacrifice," he said.

The two-day summit is being attended by officials from about 30 nations as well as delegates from major technology corporations, including Facebook, Twitter, and Google.

Social media has played a key role in helping the Islamic State group attract thousands of foreign fighters to join its so-called Islamic caliphate, which stretches across parts of Syria and Iraq.

Over 100 Australians are thought to have joined the Islamic State. This has prompted Australia to introduce tough laws that would strip dual nationals of their citizenship if they join a terrorist group.

Australian Foreign Minister Julie Bishop said Thursday the passports of 115 Australians have been canceled, nine others have been suspended, and 14 passport applications have been refused as part of the anti-terror efforts.

Bishop also said more attention should be paid to how women can help combat extremism, warning that females make up "around one-fifth of those flocking to join ISIS," another name for the extremist group.